The report will reveal concerns about radium contamination at Dalgety Bay in Fife and at least 25 other sites across the UK. Photograph: Michael Mercer /Alamy

The Ministry of Defence (MoD) has been forced to abandon attempts to block a report by government advisers warning that radioactive contamination of military sites across the UK could pose a risk to public health.

But after the 75-page report was leaked to the Guardian, a decision was taken in Whitehall on Tuesday to publish it early next week. It will reveal that Comare is concerned about radium contamination from the second world war at Dalgety Bay in Fife and at least 25 other sites across the UK.

The contamination at Dalgety Bay poses “a potential risk to public health”, the report says. It condemns the MoD’s failure to provide a comprehensive list of other potentially contaminated sites as “unacceptable” as it “implies an unknown risk to the general population”.

Because of the “extensive” contamination, parents should be recommended not to allow their children to dig on the beach, the report says. Although it concludes that there is no immediate evidence of increased cancers, it points out that side-effects can take time to appear and recommends a study of cancer rates to be carried out around Dalgety Bay in five or 10 years.

Comare’s report recommends that the Scottish government should ensure that Dalgety Bay is cleaned up as soon as is possible. An evaluation of the best means of remediation should be instituted immediately, “considering efficacy, practicability and cost”, it says.

According to the report, disposal of radium – used to paint aircraft dials so that they could be read in the dark – was “very widespread”. It criticises the MoD for only providing a limited list of sites where this could have happened. Though the only site named in the report is Dalgety Bay, 15 have been previously listed by the MoD.